Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities. Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA). PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
How has the most celebrated scientific theory of the 20th century held up under the exacting scrutiny of planetary probes, radio telescopes and atomic clocks? After 100 years, was Einstein right?
The problem of vacuum energy is reviewed. The observational evidence in favor of a non-zero cosmological constant is described. I then discuss several possible explanations for how a theoretically natural huge value of vacuum energy could be adjusted down to the unnaturally tiny but observed value.
At the turn of the century, numerous figures were attempting to form a new unitary science of psychology, modelled on how they imagined sciences like physics and chemistry functioned, with the discovery of universal laws and discoverers who would be proclaimed to be on the scale of Copernicus and Newton. It was intended that the formation of this new science would be nothing less than the completion of the scientific revolution, and that as a consequence, it would transform psychiatry, psychotherapy, the human sciences and indeed, all walks of life.
Few, if any, papers have attracted as much attention as Einsteins June paper on the Special Theory of Relativity and no equation of physics has become part of common discourse except for the equation Einstein presented in his September paper: E = mc2. The concepts of space and time are ubiquitous in physics and, since the Special Theory of Relativity fundamentally altered these concepts, the impact of the June paper on physics has been pervasive. With the additional assertion, made in the June paper, that the speed of light is a constant for all observers, time and space became relative.
This talk will take you on a tour through the mind of Albert Einstein, focussing on his discoveries of 1905 and the vital role his theories play in many of today\'s technologies.
In 1905, there were prominent scientists who did not believe in atoms. Einstein did. His April and May papers were motivated in part to support the concept of atoms. The April paper, Einsteins dissertation and one of his most cited papers, shows how the dimensions of a sugar molecule, suspended in water, can be determined. His method had many practical applications, hence the citations. In the May paper, a pollen particle took the place of a sugar molecule. For decades, the irregular, zig-zagging motion of pollen particles was a mystery.
Einsteins March paper, the only paper that Einstein himself called revolutionary, directly challenged the firm beliefs of all physicists. With compelling evidence in their support, physicists regarded the nature of light as a closed chapter: light was a continuous electromagnetic wave. Einstein countered this entrenched belief with the claim that light was a stream of discontinuous, isolated particles. The age-old conundrum of continuity vs. discontinuity was again called into play.